1. Field of the Invention
This invention relates to and has among its objects the provision of novel needle assemblies. It is a particular object of the present invention to provide a needle assembly for use in the collection of blood from a donor. Further objects of the invention will be evident from the following description wherein parts and percentages are by weight unless otherwise specified.
2. Description of the Prior Art
In conventional blood banking practice, blood is collected from a donor into a sterile, flexible, plastic container (donor bag), which is usually part of a blood bag system to be used in the processing of the collected blood into components. The donor bag generally contains an anticoagulant which mixes with the collected blood. Attached to the donor bag by means of flexible tubing is a needle for making a venipuncture in the donor's arm. It is, of course, mandatory to maintain the sterile integrity of the needle used for the venipuncture. If the needle is contaminated it could be dangerous to the blood donor, and the contamination could be washed into the collected blood. The needle should operate with minimal discomfort to the donor.
Conventional donor needles usually comprise a needle normally with a sharpened forward end for the venipuncture, a needle-retaining means, and a needle protector. Customarily, blood bag systems are sterilized after assembly. During the sterilization procedure droplets of anticoagulant may enter the needle and pass into the needle protector. This anticoagulant liquid adheres to the needle surface and during venipuncture may cause an unpleasant stinging sensation in a donor or at least cause apprehension in the mind of a donor. Removal of the liquid by wiping the needle surface after the needle protector is removed is difficult because sterility must be maintained.
Some workers have approached the above problem by designing a needle protector with a front portion with an inside diameter approximately the same diameter as the needle's outside diameter, therefore fitting tightly around the needle (U.S. Pat. No. 3,523,530). In this way anticoagulant solution in a donor bag is kept from leaking out of the needle and filling the protector. However, such an approach is less than satisfactory for removing residual liquid on the full surface of the needle. Such liquid may get in the needle protector during sterilization of the blood bag assembly. Steam sterilization is generally employed and causes the anticoagulant in the donor bag to vaporize, a situation which is actually necessary for the sterilization of the needle.
It is also known to imbed the needle in a rubber or cork stopper (U.S. Pat. Nos. 2,688,963; 2,667,163; 2,688,964; 3,416,657). However, this approach is disadvantageous not only because of the deleterious impact on sterilization but also because the needle point may become either damaged or coated with particles or both.
Other needle assemblies for parenteral use are known in the art. For example, donor needles for blood donor assemblies are described in U.S. Pat. Nos. 2,689,562 and 4,091,811. U.S. Pat. Nos. 2,938,238; 3,406,687; and 3,523,531; disclose needle assemblies for parenteral administration; and syringes are disclosed in U.S. Pat. Nos. 2,708,438; 1,494,973; and 3,416,657.